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SHARK: Flying a self-contained capsule with an UHTC-

based experimental nose

Roberto Gardi

1, Antonio del Vecchio

2, Giuliano Marino

3,Gennaro Russo

4

C.I.R.A. Italian Aerospace Research Centre, Via Maiorise snc, 81043 Capua (CE), Italy

SHARK (Sounding Hypersonic Atmospheric Re-entering ‘Kapsule’) is a small capsule

designed and realized by CIRA. It was launched on March the 26th 2010 on board the

European Space Agency sounding rocket MAXUS 8 flight. During the ascent parabola, the

capsule was released and successfully executed its 15 minutes ballistic flight and then re-

entered in the atmosphere and landed.

The aim of the project was to prove the possibility to set up a low cost experimental space

platform and execute a re-entry test flight by dropping a capsule from a sounding rocket.

Since CIRA is investigating new technologies for the re-entry and in particular new

ceramic materials for sharp thermal protection systems (TPS), this flight opportunity has

been chosen to test in a real flight an UHTC (Ultra High Temperature Ceramic) component,

machined from scraps of previous ground tests executed in the Plasma Wind Tunnel

SCIROCCO.

The paper describes the mission genesis and development, the design and the subsystems

of the capsule and then shows the first results from the preliminary analysis of the recorded

data.

Nomenclature

CIRA = Italian Aerospace Research Centre

ESA = European Space Agency

MIP = Mandatory Inspection Procedure

PWT = Plasma Wind Tunnel

SSC = Swedish Space Corporation

TPS = Thermal Protection System

UHTC = Ultra High Temperature Ceramic

1 SHARK responsible, r.gardi@cira.it.

2 Researcher, a.delvecchio@cira.it.

3 Project Manager. g.marino@cira.it.

4 Space System Division Manager, g.russo@cira.it.

17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 11 - 14 April 2011, San Francisco, California

AIAA 2011-2305

Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

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I. Introduction

HARK (Sounding Hypersonic Atmospheric Re-entering

‘Kapsule’) is a small capsule designed and realized by

CIRA. On March the 26th 2010, the European Space Agency

sounding rocket MAXUS 8 was launched. During the ascent

parabola, the capsule was released and successfully executed its

15 minutes ballistic flight and then re-entered in the atmosphere

and landed.

The aim of the project was to prove the possibility to set up

a low cost experimental space platform and execute a re-entry

test flight by dropping a capsule from a sounding rocket.

Since CIRA is investigating new technologies for the re-

entry and in particular new ceramic materials for sharp thermal

protection systems (TPS), this flight opportunity has been

chosen to test in a real flight an UHTC (Ultra High Temperature

Ceramic) component, machined from scraps of previous ground

tests executed in the Plasma Wind Tunnel SCIROCCO.

One of the most remarkable aspects of this project is the

schedule. The first informal contacts occurred between CIRA

and ESA at the end of July 2009. The first official commitment

from ESA was transmitted in September of the same year, on

the basis of a feasibility study performed by CIRA. Then the

detailed design was accomplished and the procurement of all

parts was activated. The final integration and functional tests were performed in three days from February 4 to 6

(including a Saturday and a local holiday). The following Wednesday, February the 10nd

2010, the capsule was

already in the SSC headquarter in Stockholm for the MIP. The capsule was there accepted and handed over in less

then 4 months since the first official commitment.

II. SHARK Mission Overview

The rocket has been launched at 13:43 UT from the

Swedish space base ESRANGE (Kiruna). SHARK

separation occurred 90s after the ignition, at a 192km

altitude, when the vehicle was flying at 3km/s with an 88°

flight path angle. At that time the capsule electrical

systems was activated and the onboard computer started to

acquire data. Acquisition continued smoothly during the

ballistic flight up to 700km altitude (apogee), during the

downward trip, the atmospheric re-entry and landing.

To be cheep, SHARK was not equipped with a

parachute and telemetry; the survival of the data in the

memory unit has been successfully achieved with a very

strong design of the hull that has protected the internal

systems during all the phases.

The radio beacon signal was not received by the

satellite network the day of the launch, then the recovery

the same day was not possible.

The capsule was then recovered in July the 1st when

the localization was allowed by the melting of the snow.

The metallic structure was found in very good condition,

the paint on the frontal shield was totally removed by the aerodynamic heating, while it was intact on the back,

proving that the re-entry attitude was nominal.

S

Figure 2. SHARK as found in July the 1st 2010

Figure 1. SHARK Capsule fully integrated. It

is visible the grey UHTC tip

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The interior of the capsule was in relatively

good conditions too, despite the ground impact

the memory unit was in perfect condition and the

downloaded data shows that the computer

continued to acquire even after the landing,

recording data on the cooling of the capsule in the

snow.

Preliminary data analyses show that the

UHTC tip has suffered damages during the re-

entry, caused by the very high thermal stress. The

rupture was probably triggered by small defect

introduced during the machining of the

component or during the last ground tests. The

mechanical interface was designed to crush inside

the capsule, allowing to part of the ceramic to

survive the impact, offering the possibility to

perform post flight analyses on the flown UHTC.

During the re-entry, the UHTC was exposed

to about 9MW/m2 heat flux and the whole

capsule sustained more than 40g deceleration

(data analyses are still running).

III. UHTC

The Italian scientific and industrial community owns the know-how needed for the fabrication of very high

quality ceramic materials, and UHTC in particular. Italian UHTCs are characterized by very good thermal and

mechanical properties. CIRA then is investigating the possible utilization of these exceptional materials for space

and hypersonic vehicles. With the objective to fill the gap between the laboratory scale specimens and the real world

application, CIRA is executing many tests in different conditions and with different UHTC systems and geometries,

tracking the boundaries of the possible application fields. The experimentation is conducted mostly on the ground,

with the 70MW plasma wind tunnel SCIROCCO, but with SHARK, EXPERT, IXV and SCRAMSPACE, CIRA is

moving the experimentation from the ground to the real flight environment.

The image beside

shows the map of the

test already executed

and planned on

structures based on

UHTC.

Nose 1 and Nose 2

are test article tested in

PWT. The Nose_2

sustained also another

test, designed to be the

last test performed on

this specimen, aimed

to find the real limit of

the structure. The

experiment lasted 29

seconds at the highest

heath flux available in

the facility.

PL_15 PWT refers

to the test on the EXPERT payload, aimed to evaluate the behaviour of the flight model. PL 15 ‘volo’ refers to the

real flight condition of the capsule EXPERT that shall be flown in the late 2011. FTB 4 IXV and SCARMSPAVE

(not yet shown in the plot) are flight experiment still under consolidation.

Front shield

OBDH

Radio beacon

Pressure

transducers

Accelerometer

Rate

sensors

UHTC tip

Thermocouples

Beacon antenna

Back shield

Insulator

Preloaded spring

Figure 3. SHARK 3D model

Nose 1

Nose 2 Test 1

Nose 2 Test 2

MAXUS

FTB-4IXV

PL 15 Volo

PL 15 PWT

0

500

1000

1500

2000

2500

UHTC Eperiment

Tem

pera

ture

[°C

]

Figure 4. MAXUS/SHARK experiment in the map of the UHTC experiments

activities performed and planned by CIRA

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IV. Capsule Design

SHARK has been conceived in the fall 2009 after some informal iteration. The first official commitment from

ESA was signed in September the 30th

. In order to meet the Mandatory Inspection milestone, hold in February the

10th

in SSC, CIRA operated at full speed for the definition of the design, manufacturing of the structural parts,

procurement of sensors, onboard data system, localization beacon, components of the power system and all the

many parts that compose the 20kg of SHARK

The design was aimed to be simple, reliable and based on COTS components with short procurement time. The

mass availability, limited by the separation systems chosen, was used to build a very strong stainless steel frontal

shield able to bear thermal and

mechanical loads, and an aluminium

rear part, that keeps the barycentre of

the capsule as aft as possible, with

benefits for the stability of the

atmospheric part of the flight.

The data handling system was based

on a flight proven, ACRA KAM 500

modular computer, able to acquire and

store, on a ruggedized memory unit, all

the data measured by transducers,

acquired up to 8 KHz frequency

The data acquisition and recording

capabilities of the OBDH have been

intensively used. The chosen

configuration was able to acquire 15 thermocouples and 16 analogical channels. All the TC channels have been

connected to K-type thermocouples, three installed inside the UHTC tip, some in the fore region, close to the

external surface, aiming to measure the effect of the aero-thermal heating, and some in the inside of the vehicle, in

order to evaluate the effects of the heating on the internal systems. Ten of the 26 analogical channels have been used

for the 0-100mV output of the Kulite pressure transducers. The remaining six channels have been used for the -5V /

+5V output of the tri-axial accelerometer and for the three rate sensors. Because the voltage output mismatch, a

dedicate voltage regulator has been designed and realized.

The localization of the capsule was based on a satellite emergency locator system, operating on the 406MHz, and a

homing signal acquired by the

recovery team at 120MHz

The power system was composed

by an array of lithium primary

batteries connected to the systems

by a reliable safety switch,

mechanically activated by the

separation of the capsule from the

launch vehicle. The OBDH has its

own power regulation systems, so

the batteries were directly

connected to it. The 10V power

supply, for the pressure

transducers, was provided by the

acquisition module. The dual

power supply, for the accelerometers and rate sensors, was derived from the OBDH power supply circuit, with a

dedicated board. The activation of the main switch also powered a trigger circuit that connected the radio beacon

own batteries to the transmitting unit. Since the radio beacon was required to operate even after the crash landing, a

very high reliability was required then the trigger circuit was designed to be independent from the main battery pack,

and was able to keep the beacon transmitting, using its own batteries, even if the main battery pack was damaged at

impact.

Figure 5. SHARK during the final integration

Data line

Power line

Mechanical

connection.

Figure 6. SHARK functional diagram

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V. Data processing and analyses

A. Preliminary processing and beacon interference

Since the activation of the capsule, at the separation from the payload stage, all the sensors have operated

correctly and the data have been recorded in the main memory unit. Only one of the rate sensors was offline, but it

was non operative since the delivery (it is likely that it was damaged during the transportation). The following table

resumes all the data acquired during the flight:

Sensor Range Quantity Frequency [HZ]

Front shield temperature K-type thermocouple -100 +1100°C 9 64

UHTC Temperature K-type thermocouple -100 +1100°C 3 64

Back shield Temperature K-type thermocouple -100 +1100°C 3 64

Computer Temperature RTD (cold joint) -55 +125°C 1 64

Front shield pressures Kulite XTEL-190 0 25 PSIa 7 512

Back shield pressures Kulite XTEL-190 0 2 PSIa 3 512

Accelerations (triaxial) SD 2430 -100 +100 g 1 8192

Angular rates SDG 500 -100 +100 °/s 3 512

Table 1 Transducer types, quantity, ranges and acquisition rates.

The data acquisition system

converted the signals produced by

the transducer into 16bit integer

numbers, ranging from 0 to 65536.

According to the sensitivity of

each sensor the integer are translated

in double precision numbers,

representing the measured value into

engineering units.

Sensitivity and zero shifts used

for the pressure transducers have

been taken from the calibration

certificates of each item.

The data acquired during the

flight shows some non physical

behaviour caused by the acquisition

system. These errors are limited in

time, they do not affect the

usefulness of the measure, but they

require a correction. These errors

affect all the channels at the same

instant and have the same timing of

the 5 Watts signal transmitted by

Kannad 406 radio beacon.

The interference affects the data

for a very short time and in a way

that make easy to identify the real

data and the interference. Anyway

the correction was carried out

channel by channel, interference by

interference. The images beside

show the work performed on an

accelelrometric channel.

Figure 7 Preliminary processing on accelerations signals acquired

during the flight

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B. Offsets

The data are divided in three main sets, the acquisition performed at the functional test, the acquisition performed

during the flight and the data acquired after the landing. These sets are named Event_0 Event_1 and Event_2

respectively.

During the on ground functional test all the transducers, excluding the rate sensors, have been acquired in steady

conditions. More over, during the extra atmospheric phase of the flight the acceleration and the pressure are known

to be zero. These two considerations can be used to correct offsets errors.

Accelerations have been acquired in all three events.

During Event_0 the capsule was steady and with Z axis at more or less perpendicular to the local horizon.

During the extra atmospheric part of Event_1 the capsule is in micro gravity conditions and it is spinning at a

very low rate 10-15 deg/s.

At 800s, in Event_1, the accelerations get almost steady again, this is because the strong deceleration at interface

is over and the capsule is falling at almost constant speed. In this phase there are residual oscillations.

During the Event_2 the capsule is steady again and is likely that the Z axis of the capsule was at more or less

aligned with the local vertical axis.

The acceleration a caused by the spinning during the free fall is given by:

Ra2

ω=

Where ω = 15deg/s = 0.26rad/s is the angular velocity and R=15cm is the distance between the accelerometer

and the CoG of the capsule. Computation results in a negligible value for a = 0.01 m/s2 = 0.001g.

Here below are resumed the expected and measured values for each case:

Event_0 Event_1a Event_1b Event_2

Exp. Meas. Exp. Meas. Exp. Meas. Exp. Meas.

Axis X <1 -0.65 0 -0.64 ~0 -0.66 <1 -0.46

Axis Y <1 0.62 0 1.06 ~0 1.02 <1 0.74

Axis Z <1 1.54 0 0.69 ~1 1.75 <1 1.56

Modulus 1 1.79 0 1.45 ~1 2.15 1 1.80

Table 2 Comparison of expected and measured values for the four phases.

Since the attitude in phases “0” and “2” is not well known and during the event “1b” the drag effect cannot be

predicted without a direct measure of altitude attitude and velocity, the most useful event for the correction of the

offsets values is the “1a”.

Three offsets values have been chosen in order to have zero acceleration in event_1a and have been applied to all the

other events:

Event_0 Event_1a Event_1b Event_2 Correction

Axis X -0.01 0 -0.02 0.18 0.64

Axis Y -0.44 0 -0.04 -0.32 -1.06

Axis Z 0.85 0 1.06 0.87 -0.69

Modulus 0.96 0.00 1.06 0.94

Table 3 Measured values corrected and correction amount.

The results of correction are very good, the residual errors, with respect to the expected values, are less than 0.06g

that is 0.06% of the full scale output.

A very similar procedure has been carried out for the pressure transducers.

During Event_0 the capsule was steady and all the pressure ports were sensing the same room pressure.

During the extra atmospheric part of Event_1 the transducers were exposed to vacuum, zero PSI.

During the Event_2 the capsule was steady again and all the pressure ports were sensing the same room pressure. In

this phase one of the transducer was lost.

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The part of the flight outside the atmosphere permits to correct the zero offsets of the measured pressures. The

results of this correction are in the following table:

Pressure port Event 0 Event 1 Event 2 Offset correction

Front shield (25 PSI FS)

P01 14.5736 0.0000 13.6037 -0.0556

P02 14.7561 0.0000 13.8990 0.0062

P03 5.8171 0.0000 5.3818 -0.0405

P05 14.5609 0.0000 13.7555 -1.0414

P06 14.5464 0.0000 13.4482 0.1375

P08 14.5540 0.0000 13.7157 -0.2689

P09 14.5563 0.0000 NA -0.0726

Front shield (5 PSI FS) [PSI]

P04 4.4086 0.0000 4.4086 -0.0915

P07 4.3886 0.0000 4.3886 -0.0831

P10 4.4929 0.0000 4.4929 -0.1180

Table 4 Mean values of pressure corrected for the zero offset.

The pressure during the Event 0 is not known, but can be assumed that the best evaluation of room pressure is given

by the mean of the pressure measured by the 7 pressure transducers (PT 04, 07 and 10 are out of range in room

conditions)

This permits to compensate the sensitivity in order to have the same reading on all the channels at room conditions.

Pressure port Event 0 Event 1 Event 2 Sensitivity

correction

Front shield (25 PSI FS)

P01 14.3754 0.0000 13.4187 0.9864

P02 14.3754 0.0000 13.5404 0.9742

P03 14.3754 0.0000 13.2997 2.4712

P05 14.3754 0.0000 13.5803 0.9873

P06 14.3754 0.0000 13.2901 0.9882

P08 14.3754 0.0000 13.5474 0.9877

P09 14.3754 0.0000 N.A. 0.9876

Table 5 Mean values of pressure corrected for the zero offset and sensitivity.

The corrected values during event

2 have a residual discrepancy

smaller then 0.3 PSI that

corresponds to 1.2% of the full

scale output. The results of this

activity are shown in the diagram

beside. They show some of the

pressure channels before and after

the correction.

Figure 8 Measured and corrected pressure for PT 01, 02, 05, 08, 03, 06

and 09

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C. Filtering

Signals are filtered by means of discrete Fourier transform (DFT)

thought the following steps:

The Mirroring of the signal consist in appending to the original

sequence the same sequence inverted in time, in order to perform the

DFT on a even function, where f(tmin) = f(tmax)

The spectrum cutting consists in erasing the frequencies above a

chosen cut frequency.

The goodness of the fitting is measured:

1. by visual inspection

2. evaluating the normalized energy variation between the original

and filtered signal, numerically calculating the area below the two

curves

3. evaluating the Coefficient of determination R2 as:

Where:

yi is the non filtered value at measured at time ti

fi is the filtered value at measured at time ti

yi is the mean of all yi

In order to have smooth curves, the filtered signal is re-sampled with a resample frequency higher than the cut

frequency. This permits to reduce the size of the vector maintaining a smooth reconstruction of the curves.

Here after are shown the spectra and the filtered and unfiltered temperatures. The chosen cut frequency is 2Hz,

and the resample frequency: 20Hz

( )

( )∑

∑

−

−

−=

i

i

i

ii

yy

fy

R2

2

2 1

Mirroring

DFT

Spectrum cutting

Inverse DFT

Is fitness

good?

Resample the

filtered signal

Original signal

Filtered signal

Figure 9. Signal filtering flow chart

Figure 10 Front shield temperatures spectra and filtered signals.

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The following tables show the energy variation and the R2 value for all the TC channels.

TC Number Normalized energy variation (E) R2

09 0.0061 1.0000

10 0.0063 1.0000

14 0.0045 0.9994

01 2.1213e-004 1.0000

02 6.9397e-004 1.0000

05 1.9166e-004 1.0000

06 3.1676e-004 1.0000

07 3.9868e-004 1.0000

08 2.0083e-004 1.0000

11 3.1418e-004 1.0000

12 3.2280e-004 1.0000

13 3.7187e-004 1.0000

03 3.6952e-004 1.0000

04 3.5110e-004 1.0000

15 3.7898e-004 1.0000

Table 6 Front shield temperatures goodness of fit.

Very similar filtering has been performed for the pressures, the cut frequency: is 10Hz and the resample

frequency: 20Hz. Here after is shown an exemplum.

Figure 11 Filtered and non filtered pressure from port 01 and a zoomed detail (right)

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PT Number Normalized energy variation (E) R2

01 2.7968e-005 0.9999

02 2.7869e-005 1.0000

03 2.9058e-005 1.0000

05 2.7760e-005 1.0000

06 2.8449e-005 1.0000

08 2.6847e-005 1.0000

09 2.7668e-005 1.0000

04 8.2057e-005 0.9999

07 8.1591e-005 0.9999

10 8.0006e-005 0.9999

Table 7 Back shield temperatures goodness of fit.

Very effective is the filtering of the accelerometer channels. The chosen cut frequency is 9Hz and the resample

frequency is 450Hz. This re-sapling permitted to reduce the size of the data, making them much easier to be

processed.

Axis Normalized energy variation (E) R2

X -1.4557e-007 0.9878

Y -3.6393e-005 0.9236

Z 4.0364e-006 0.9990

RY 0.0033 1.0000

RZ 4.1103e-004 0.9998

Table 8 Extra atmospheric rates goodness of fit

Figure 12 Filtered and non filtered acceleration

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D. Final data and preliminary interpretation

1. Temperatures

Temperatures

stay almost

constant for the

extra atmospheric

part of the flight.

The slaw heating

can be caused by

the power

dissipation of the

internal system. At

reentry interface,

the temperatures

rise quickly.

The TC closer

to the nose (TC1,

TC5 and TC8)

experience higher

temperatures.

Figure 13 Temperatures on the frontal shield of the capsule.

Figure 14 Temperatures on the frontal shield of the capsule and a detail of the

atmospheric part of the flight.

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The thermocouples

on the back shield

experience much lower

temperatures. Heat is

transmitted mostly by

conduction through the

structure of the capsule.

The UHTC

experience a very quick

heating (up to 9

MW/m2). The thermo-

couples are inserted and

glued in a hole drilled in

the UHTC Tip.

The data are lost

when the tip breaks and

the thermocouples get

exposed to the external

environment. The

heating rate (up to XX

MW/m2/s) has to be

compared with the

numeric simulations.

The measure permit to

find the real heat flux

impinging on the tip.

Figure 15 Temperatures on the back shield of the capsule.

09

14

10

Figure 16 Temperatures on the UHTC tip, detail of the atmospheric part of the

flight.

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2. Pressures

The pressure is zero

during the extra-

atmospheric part of the

flight. This will permit

to better correct the

offset error of the

transducers.

During the

atmospheric part of the

flight the pressures

show an oscillating

behavior, indicating the

oscillations of the

capsule around its

equilibrium attitude.

Comparison the phases

of the oscillations of

the transducers placed

in different radial

positions, can give

indications on the

attitude.

Transducers on the

sides of the cylindrical

part measure lower

pressure. At 780s is the

time when the

deceleration stops and

the capsule proceeds at

constant speed.

It is very interesting

to note that these

sensors between 775s

and 780s sense the

supersonic / subsonic

transition.

Figure 17 Pressures on the frontal shield of the capsule, detail of the

atmospheric part of the flight.

Figure 18 Pressure on the back shield of the capsule.

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3. Accelerations

Accelerations are

negligible in the extra

atmospheric phase. This

shall permit to better

remove the offset errors.

Such errors are

introduced also by the

resistances used to lower

the voltage from ±5V to

±100mV. In Z direction

40g are exceeded.

The accelerations

show the same

oscillations of the

pressures. In the steady

velocity part of flight the

Z acceleration is 1g

higher than in the extra-

atmospheric phase.

4. Angular rates

Rate sensor along X

direction was not

functioning since the

integration.

During the extra

atmospheric part of the

flight the angular

velocity are low. When

the capsule starts to

oscillate in the

atmosphere they grow

quickly.

Figure 19 Components of the acceleration, detail of the atmospheric part of the

flight.

Figure 20 Angular rates measured during the flight.

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The two survivor

rate sensors can give

indication of the

motion of the capsule

around the barycentre,

after the separation and

before the interface

with the atmosphere.

The rate sensors

range has been chosen

to be effective in the

extra-atmospheric part

of the flight. The

stronger oscillations in

the first part of the

atmospheric flight

caused saturation of the

rate signals.

Figure 21 Angular rates, detail of the extra-atmospheric part of the flight.

Figure 22 Angular rates, detail of the atmospheric part of the flight.

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In order to have better results, the signal has been

reconstructed before proceeding with filtering.

An attempt has been made to rebuild the missing data

by interpolating the available data with a spline

function.

The acquired points affected by the saturation error

have been removed from the original signal.

The missing points have been interpolated using the

error free points.

The goodness of the reconstruction has been

evaluated applying the same algorithm to a part of

signal where there is no saturation, but an artificial

saturation has been simulated. The result is in the

following image.

Figure 23 Part of signal affected by saturation and

spline reconstructed signal

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E. UHTC rupture

In the following two figures the temperature measured by the thermocouples in the UHTC tip and the pressure

measured by two pressure ports close to the tip are shown. It is evident that after the instant 762s (when the TC data

are meaningless) there is

also an abrupt change in the

behaviour of the pressures.

We can deduce that at 760

seconds the rupture of the

UHTC started and that two

seconds later the tip broken

apart, changing the

aerodynamic environment

around the capsule.

Since the pressure

transducers have a very high

cut frequency, and they have

been acquired at 512 Hz, it

is possible to filter the

signals in the audible

frequencies.

The signals have been

filtered removing all the

components below 40Hz

and above 245Hz. The

results are in the following

diagram.

The last diagram shows the

noise caused by the dynamic

pressure in the 760s – 772s

interval and after 780s by

the low altitude pressure. At

762s is recorded the noise

caused by the rupture of the

UHTC tip.

Figure 24 Temperatures and pressured at the rupture insyant

Figure 25 Detail of UHTC temperatures and pressure ports

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VI. Conclusion

SHARK is the first self-contained (black box) small space capsule flown in Europe. It was fully designed,

realized and qualified at CIRA.

The mission was performed in nominal way. The presence of SHARK has not degraded the main mission of the

rocket and has not affected the main payload experiments.

The design and all the subsystems have proven to be able to survive the launch solicitation.

All the internal systems have operated in nominal way during the flight.

The robust design allowed almost all the subsystems to survive also at the impact. The computer acquired data

during the flight and for 5 hours after the landing, until the memory unit was full. 4GB of data are available for

scientific investigation.

The data have been analyzed, cleaned with respect to some interferences caused by the radio beacon, and filtered

in order to remove noise.

All the acquired data have a very good quality and permit to identify all the most important events of the flight.

The UHTC component was exposed to the hypersonic environment and sustained a very quick and intense heating,

until a crack, probably generated by a defect introduced by the machining of the thermocouples hole, has broken the

tip of the ceramic cone.

The data are actually under further investigation and comparison with numerical simulations.

Acknowledgments

The authors would like to acknowledge Antoine Bavandi (formerly working at ESA) who was the originator of

the flight opportunity and technical officer of the ESA contract, Nuno Filipe (formerly working at ESA) for his

valuable support to the activity. Many people in ESA have believed in this challenging project, among them the

authors would aknnowledge Simonetta Di Pippo, Antonio Verga, Guillermo Ortega, Fabio De Pascale, Giancarlo

Bussu.

The work of many SSC people was absolutely remarkable, the authors would be happy to recall Gunnar Florin,

Jimmy Thorstenson, Thomas Karlsson and all the people that worked very hard in ESRANGE. Last but not least, the

authors express deep appreciation for the work and the professionalism of the EADS Astrium people, leaded by

Andreas Shutte.

American Institute of Aeronautics and Astronautics

19

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